Amplitude analysis and branching fraction measurement of the decay D+ → $$ {\textrm{K}}_{\textrm{S}}^0 $$ π+π0π0

Journal of High Energy Physics, Sep 2023

Using 2.93 fb−1 of e+e− collision data collected with the BESIII detector at the center-of-mass energy 3.773 GeV, we perform the first amplitude analysis of the decay D+ → $$ {K}_S^0 $$ π+π0π0 and determine the relative magnitudes and phases of different intermediate processes. The absolute branching fraction of D+ → $$ {K}_S^0 $$ π+π0π0 is measured to be (2.888 ± 0.058stat. ± 0.069syst.)%. The dominant intermediate processes are D+ → $$ {K}_S^0 $$ a1(1260)+(→ ρ+π0) and D+ → $$ \overline{K} $$ *0ρ+, with branching fractions of (8.66 ± 1.04stat. ± 1.39syst.) × 10−3 and (9.70 ± 0.81stat. ± 0.53syst.) × 10−3, respectively.

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Amplitude analysis and branching fraction measurement of the decay D+ → $$ {\textrm{K}}_{\textrm{S}}^0 $$ π+π0π0

Published for SISSA by Springer Received: May 26, 2023 Accepted: August 22, 2023 Published: September 12, 2023 The BESIII collaboration E-mail: Abstract: Using 2.93 fb−1 of e+ e− collision data collected with the BESIII detector at the center-of-mass energy 3.773 GeV, we perform the first amplitude analysis of the decay D+ → KS0 π + π 0 π 0 and determine the relative magnitudes and phases of different intermediate processes. The absolute branching fraction of D+ → KS0 π + π 0 π 0 is measured to be (2.888 ± 0.058stat. ± 0.069syst. )%. The dominant intermediate processes are D+ → KS0 a1 (1260)+ (→ ρ+ π 0 ) and D+ → K̄ ∗0 ρ+ , with branching fractions of (8.66 ± 1.04stat. ± 1.39syst. ) × 10−3 and (9.70 ± 0.81stat. ± 0.53syst. ) × 10−3 , respectively. Keywords: Branching fraction, Charm Physics, e+ -e− Experiments, Particle and Resonance Production ArXiv ePrint: 2305.15879 c The Authors. Open Access, ⃝ Article funded by SCOAP3 . https://doi.org/10.1007/JHEP09(2023)077 JHEP09(2023)077 Amplitude analysis and branching fraction measurement of the decay D+ → K0Sπ +π 0π 0 Contents 1 Introduction 1 2 Detector and data sets 2 3 Event selection 3 4 4 4 7 8 10 11 12 5 BF measurement 14 6 Summary 19 sig tag A Two-dimensional fit on MBC versus MBC 21 B Other tested intermediate processes 22 C The interference between processes 24 The BESIII collaboration 27 1 Introduction Hadrons containing a charm quark play an essential role in studies of the strong and weak interactions. The lightest charmed mesons, D0(+) , can decay only through the weak interaction and their masses place them in the region where perturbative Quantum Chromodynamics is not applicable [1]. These facts do not significantly affect the theoretical prediction of leptonic and semileptonic decays but impose difficulties in hadronic decays [2]. Measurements of amplitudes and branching fractions (BFs) of charmed meson hadronic decays could provide useful information about the underlying decay mechanism and help to improve theoretical calculations. The Cabibbo-favored decay D+ → KS0 π + π 0 π 0 has been previously observed by BESIII with a BF of (2.904 ± 0.062stat. ± 0.087syst. )% [3]. However, the corresponding detector efficiency was obtained by mixed-signal Monte Carlo (MC) samples, which can now be improved by using an amplitude model. An amplitude analysis of this four-body decay, compared to well-measured three-body decays [4–6], can also help us better understand the more complicated dynamics and substructures in the processes D+ → V V and D+ → AP , where V , A, and P denote vector, axial-vector and pseudoscalar mesons, respectively. The –1– JHEP09(2023)077 4 Amplitude analysis 4.1 Further selection criteria 4.2 Fit method 4.2.1 Blatt-Weisskopf barriers 4.2.2 Propagator 4.2.3 Spin factors 4.3 Fit results 4.4 Systematic uncertainties for the amplitude analysis 2 Detector and data sets The BESIII detector is a magnetic spectrometer [11, 12] located at the Beijing Electron Positron Collider (BEPCII) [13], which records symmetric e+ e− collisions in the center-ofmass energy range from 2.0 to 4.95 GeV, with a peak luminosity of 1×1033 cm−2 s−1 achieved √ at s = 3.77 GeV. The cylindrical core of the BESIII detector covers 93% of the full solid angle and consists of a helium-based multilayer drift chamber (MDC), a plastic scintillator time-of-flight system (TOF), and a CsI(Tl) electromagnetic calorimeter (EMC), which are all enclosed in a superconducting solenoidal magnet providing a 1.0 T magnetic field. The solenoid is supported by an octagonal flux-return yoke with resistive plate counter muon identifier modules interleaved with steel. The charged-particle momentum resolution at 1.0 GeV/c is 0.5%, and the specific ionization energy loss (dE/dx) resolution is 6% for the electrons from Bhabha scattering. The EMC measures photon energies with a resolution of 2.5% (5%) at 1 GeV in the barrel (end-cap) region. The time resolution in the TOF barrel region is 68 ps, while that in the end-cap region is 110 ps. √ Data samples corresponding to a total integrated luminosity of 2.93 fb−1 at s = 3.773 GeV are used in this analysis. This energy is slightly higher than the resonance peak of the ψ(3770), which predominantly decays to D+ D− or D0 D̄0 pairs without any additional hadrons, thereby providing an ideal environment for studying D meson decays with the double-tag (DT) technique [14]. In this method, a single-tag (ST) candidate requires only one D− to be reconstructed via hadronic decays. In a DT candidate, both the D+ and D− mesons are reconstructed, with the D+ meson decaying to the signal mode D+ → KS0 π + π 0 π 0 and the D− meson decaying to one of the ST modes. Simulated inclusive MC samples are produced with a geant4-based [15] MC simulation package, which includes the geometric description of the BESIII detector [16] and the detector response, and are used to determine detection efficiencies and to estimate backgrounds. The simulation models the beam energy spread and initial state radiation (ISR) in the e+ e− annihilations with the generator kkmc [17, 18]. The inclusive MC samples consist of the production of DD̄ pairs, the non-DD̄ decays of the ψ(3770), the ISR production –2– JHEP09(2023)077 BF of D+ → K̄ ∗0 ρ+ , which is a Cabibbo-favored D+ → V V process, can be measured more precisely in comparison to the previous MARK III result [7]. An amplitude analysis can provide inputs for polarization studies to check the reliability of different theoretical models [8]. Furthermore, measurements of D+ → AP decays are beneficial for our understanding of the nature of axial-vector mesons and offer global parameters in calculating the corresponding BFs [9]. The difference between the production rates of K1 (1270) and K1 (1400) can be extracted, which provide key inputs to determine the mixing between these two mesons [10]. With 2.93 fb−1 of e+ e− collision data collected by the BESIII detector at the center-of√ mass energy s = 3.773 GeV, we present the first amplitude analysis of the decay D+ → KS0 π + π 0 π 0 and update the BF based on the corresponding amplitude model. The daughter particle KS0 is reconstructed by π + π − . Charge-conjugate states are implied throughout this paper. of the J/ψ and ψ(3686) states, and the continuum processes incorporated in kkmc. All particle decays are modelled with evtgen [19, 20] using BFs either taken from the Particle Data Group (PDG) [21], when available, or otherwise estimated with lundcharm [22, 23]. Final state radiation from charged final state particles is incorporated using photos [24]. 3 Event selection MBC = q 2 Ebeam /c4 − |⃗ pD± |2 /c2 , ∆E = ED± − Ebeam , –3– (3.1) JHEP09(2023)077 The D± candidates are constructed from individual π ± , π 0 , K ± , and KS0 mesons with the following selection criteria, which are the common requirements for both the amplitude analysis and BF measurement. Further requirements are discussed in secti (...truncated)


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Ablikim, M., Achasov, M. N., Adlarson, P., Ai, X. C., Aliberti, R., Amoroso, A., An, M. R., An, Q., Bai, Y., Bakina, O., Balossino, I., Ban, Y., Batozskaya, V., Begzsuren, K., Berger, N., Berlowski, M., Bertani, M., Bettoni, D., Bianchi, F., Bianco, E., Bortone, A., Boyko, I., Briere, R. A., Brueggemann, A., Cai, H., Cai, X., Calcaterra, A., Cao, G. F., Cao, N., Cetin, S. A., Chang, J. F., Chang, T. T., Chang, W. L., Che, G. R., Chelkov, G., Chen, C., Chen, Chao, Chen, G., Chen, H. S., Chen, M. L., Chen, S. J., Chen, S. M., Chen, T., Chen, X. R., Chen, X. T., Chen, Y. B., Chen, Y. Q., Chen, Z. J., Cheng, W. S., Choi, S. K., Chu, X., Cibinetto, G., Coen, S. C., Cossio, F., Cui, J. J., Dai, H. L., Dai, J. P., Dbeyssi, A., de Boer, R. E., Dedovich, D., Deng, Z. Y., Denig, A., Denysenko, I., Destefanis, M., De Mori, F., Ding, B., Ding, X. X., Ding, Y., Ding, Y., Dong, J., Dong, L. Y., Dong, M. Y., Dong, X., Du, M. C., Du, S. X., Duan, Z. H., Egorov, P., Fan, Y. L., Fang, J., Fang, S. S., Fang, W. X., Fang, Y., Farinelli, R., Fava, L., Feldbauer, F., Felici, G., Feng, C. Q., Feng, J. H., Fischer, K., Fritsch, M., Fritzsch, C., Fu, C. D., Fu, J. L., Fu, Y. W., Gao, H., Gao, Y. N., Gao, Yang, Garbolino, S., Garzia, I., Ge, P. T., Ge, Z. W., Geng, C., Gersabeck, E. M., Gilman, A., Goetzen, K., Gong, L., Gong, W. X., Gradl, W., Gramigna, S., Greco, M., Gu, M. H., Gu, Y. T., Guan, C. Y., Guan, Z. L., Guo, A. Q., Guo, L. B., Guo, M. J., Guo, R. P., Guo, Y. P., Guskov, A., Han, T. T., Han, W. Y., Hao, X. Q., Harris, F. A., He, K. K., He, K. L., Heinsius, F. H. H., Heinz, C. H., Heng, Y. K., Herold, C., Holtmann, T., Hong, P. C., Hou, G. Y., Hou, X. T., Hou, Y. R., Hou, Z. L., Hu, H. M., Hu, J. F., Hu, T., Hu, Y., Huang, G. S., Huang, K. X., Huang, L. Q., Huang, X. T., Huang, Y. P., Hussain, T., Hüsken, N., Imoehl, W., Irshad, M., Jackson, J., Jaeger, S., Janchiv, S., Jeong, J. H., Ji, Q., Ji, Q. P., Ji, X. B., Ji, X. L., Ji, Y. Y., Jia, X. Q., Jia, Z. K., Jiang, H. J., Jiang, P. C., Jiang, S. S., Jiang, T. J., Jiang, X. S., Jiang, Y., Jiao, J. B., Jiao, Z., Jin, S., Jin, Y., Jing, M. Q., Johansson, T., Kui, X., Kabana, S., Kalantar-Nayestanaki, N., Kang, X. L., Kang, X. S., Kappert, R., Kavatsyuk, M., Ke, B. C., Khoukaz, A., Kiuchi, R., Kliemt, R., Kolcu, O. B., Kopf, B., Kuessner, M. K., Kupsc, A., Kühn, W., Lane, J. J., Larin, P., Lavania, A., Lavezzi, L., Lei, T. T., Lei, Z. H., Leithoff, H., Lellmann, M., Lenz, T., Li, C., Li, C., Li, C. H., Li, Cheng, Li, D. M., Li, F., Li, G., Li, H., Li, H. B., Li, H. J., Li, H. N., Li, Hui, Li, J. R., Li, J. S., Li, J. W., Li, K. L., Li, Ke, Li, L. J., Li, L. K., Li, Lei, Li, M. H., Li, P. R., Li, Q. X., Li, S. X., Li, T., Li, W. D., Li, W. G., Li, X. H., Li, X. L., Li, Xiaoyu, Li, Y. G., Li, Z. J., Li, Z. X., Liang, C., Liang, H., Liang, H., Liang, H., Liang, Y. F., Liang, Y. T., Liao, G. R., Liao, L. Z., Liao, Y. P., Libby, J., Limphirat, A., Lin, D. X., Lin, T., Liu, B. J., Liu, B. X., Liu, C., Liu, C. X., Liu, F. H., Liu, Fang, Liu, Feng, Liu, G. M., Liu, H., Liu, H. B., Liu, H. M., Liu, Huanhuan, Liu, Huihui, Liu, J. B., Liu, J. L., Liu, J. Y., Liu, K., Liu, K. Y., Liu, Ke, Liu, L., Liu, L. C., Liu, Lu, Liu, M. H., Liu, P. L., Liu, Q., Liu, S. B., Liu, T., Liu, W. K., Liu, W. M., Liu, X., Liu, Y., Liu, Y., Liu, Y. B., Liu, Z. A., Liu, Z. Q., Lou, X. C., Lu, F. X., Lu, H. J., Lu, J. G., Lu, X. L., Lu, Y., Lu, Y. P., Lu, Z. H., Luo, C. L., Luo, M. X., Luo, T., Luo, X. L., Lyu, X. R., Lyu, Y. F., Ma, F. C., Ma, H. L., Ma, J. L., Ma, L. L., Ma, M. M., Ma, Q. M., Ma, R. Q., Ma, R. T., Ma, X. Y., Ma, Y., Ma, Y. M., Maas, F. E., Maggiora, M., Malde, S., Malik, Q. A., Mangoni, A., Mao, Y. J., Mao, Z. P., Marcello, S., Meng, Z. X., Messchendorp, J. G., Mezzadri, G., Miao, H., Min, T. J., Mitchell, R. E., Mo, X. H., Muchnoi, N. Yu., Nefedov, Y., Nerling, F., Nikolaev, I. B., Ning, Z., Nisar, S., Niu, Y., Olsen, S. L., Ouyang, Q., Pacetti, S., Pan, X., Pan, Y., Pathak, A., Patteri, P., Pei, Y. P., Pelizaeus, M., Peng, H. P., Peters, K., Ping, J. L., Ping, R. G., Plura, S., Pogodin, S., Prasad, V., Qi, F. Z., Qi, H., Qi, H. R., Qi, M., Qi, T. Y., Qian, S., Qian, W. B., Qiao, C. F., Qin, J. J., Qin, L. Q., Qin, X. P., Qin, X. S., Qin, Z. H., Qiu, J. F., Qu, S. Q., Redmer, C. F., Ren, K. J., Rivetti, A., Rodin, V., Rolo, M., Rong, G., Rosner, Ch., Ruan, S. N., Salone, N., Sarantsev, A., Schelhaas, Y., Schoenning, K., Scodeggio, M., Shan, K. Y., Shan, W., Shan, X. Y., Shangguan, J. F., Shao, L. G., Shao, M., Shen, C. P., Shen, H. F., Shen, W. H., Shen, X. Y., Shi, B. A., Shi, H. C., Shi, J. L., Shi, J. Y., Shi, Q. Q., Shi, R. S., Shi, X., Song, J. J., Song, T. Z., Song, W. M., Song, Y. J., Song, Y. X., Sosio, S., Spataro, S., Stieler, F., Su, Y. J., Sun, G. B., Sun, G. X., Sun, H., Sun, H. K., Sun, J. F., Sun, K., Sun, L., Sun, S. S., Sun, T., Sun, W. Y., Sun, Y., Sun, Y. J., Sun, Y. Z., Sun, Z. T., Tan, Y. X., Tang, C. J., Tang, G. Y., Tang, J., Tang, Y. A., Tao, L. Y., Tao, Q. T.. Amplitude analysis and branching fraction measurement of the decay D+ → $$ {\textrm{K}}_{\textrm{S}}^0 $$ π+π0π0, Journal of High Energy Physics, 2023, pp. 1-32, Volume 2023, Issue 9, DOI: 10.1007/JHEP09(2023)077